1. Field of the Invention
This invention relates to a method and apparatus for fabricating an interior element for an automotive vehicle, such as a door lining, a body side lining, a seat back board or a rear tray and, more particularly, to an improved method and apparatus for forming such an interior element by previously preparing a sheet of covering material for the interior element, which is laminated with a cushioned padding on a reverse side of the covering sheet, and a substrate of a predetermined three-dimensional shape for the interior element, and bonding the covering sheet onto the substrate. For brevity of description, a method and apparatus for forming a door lining for an automotive vehicle will be referred to in the following.
2. Description of the Prior Art
In general, door lining of this type is made by bonding a sheet of covering material for a door lining onto a substrate for the door lining under suction or vacuum. As examples of a substrate for the door lining, there are employed an injection-molded plate of polypropylene resin having ventilating holes formed therein, a press-formed ligneous plate and the like. As examples of a sheet of covering material for the door lining, there are employed a sheet of covering material which is laminated with a cushioned padding of expanded polypropylene, a sheet of covering material which is laminated with a cushioned padding of expanded polyvinyl chloride, and the like.
An apparatus on which a conventional method of forming a door lining is performed includes support means for receiving and supporting a substrate for the door lining thereon, the support means having an uneven surface corresponding in shape to a surface of the substrate and ventilating holes, and air-absorbing means connected to the support means for applying vacuum or suction through the ventilating holes of the support means to the substrate carried on the surface of the support means.
When a door lining is to be formed by the conventional apparatus, a substrate having adhesive previously applied onto a surface thereof is prepared and put on the surface of the support means, and a covering sheet for the door lining is placed with a cushioned padding thereof facing the adhesive-applied surface of the substrate carried on the support means. In this condition, when the air-absorbing means is operated to apply suction to the substrate through the ventilating holes of the support means, the suction is applied to the covering sheet through ventilating holes of the substrate, thereby causing the covering sheet to be drawn onto the substrate. As a result, the covering sheet is bonded to the substrate. Thus, the door lining is vacuum-formed. When an injection-molded plate is to be utilized as the substrate, the ventilating holes are formed in the plate by mold means simultaneously with injection-molding of the plate by the mold means.
With the conventional vacuum-forming method, as suction is applied to the substrate and the covering sheet is drawn onto the substrate, the ventilating holes of the lining substrate become sealed by the cushioned padding of the covering sheet. As a result, uniform applying of suction to the entire covering sheet by the air-absorbing means will be prevented. Therefore, even though the covering sheet is drawn onto the substrate by suction, maximum suction from the air-absorbing means can not be applied to the entire surface of the covering sheet. As a result, lifting regions which are not bonded onto the lining substrate are produced at the covering sheet.
In order to prevent the producing of such lifting regions at the covering sheet, pressing of the lifting regions of the covering sheet against the lining substrate is generally performed utilizing any tool, e.g., a plug. However, when the lifting regions of the covering sheet are strongly pressed against the lining substrate by the tool in order to securely bond the lifting regions of the covering sheet to the substrate, tool marks are applied onto surfaces of the lifting regions of the covering sheet, so that the covering sheet may not be pressed with so large pressure. Therefore, it is difficult to cause the covering sheet to be uniformly bonded onto the entire surface of the lining substrate, without applying such tool marks onto the lifting regions of the covering sheet.